PBR in case permanent gateway goes down

[matiasniosi]

I am connected through two ISPs and using BGP (I have my own AS).
Example: ISP A: 8.8.8.8
ISP B: 9.9.9.9

If I configure a certain range of IP addresses with a PBR policy using ISP A as permanent gateway, if ISP A goes down, do you know if the switch will still route the traffic to the default gateway (that could be ISP B)?

I explain:
I configure a PBR policy to let all source IP addresses 5.5.5.5/24 use ISP A as a permanent gateway. Since I am using BGP, I have two default routes... so if one goes down I still have connectivity through the second provider.

If the link to ISP A goes down, if no permanent gateway policy is configured the traffic will still go out through ISP B since it starts using the default route to ISP B.
But if there's a PBR policy that forces the traffic to go to ISP A, if it goes down, will it still route the traffic through ISP B?

I haven't tested this, but I imagine that since I am using BGP, if the next hop is 8.8.8.8 and there is no direct connection it will route the traffic through 9.9.9.9 since it's the available default gateway. Does this work this way?

Thanks!!

[benny]

Hi,

There are multiple ways to solve your request.

- PBR to an IP that uses VRRP with tracking on an remote interface to steer the traffic
- BFD (Bi-directional Forwarding Detection)
- Static route that "follows" your BGP route (-> ip static-route ip_address [mask mask] {gateway | follows} ip_address [metric metric])

I recommend you upgrade to AOS 6.4.3.R01 latest maintenance release to get BFD, it would be the best way to implement redundancy.

Hope this helps.

B